This proposal requests funds for the establishment of a versatile, multi-user oriented laser facility at Amherst College. To permit as wide a range of biomedical applications as possible, two independent laser systems are envisioned. The continuous ion-dye laser, together with a double monochromator and photon-counting detection would be used primarily for spectroscopic experiments (resonance Raman, emission). A pulsed Nd:YAG/dye laser with rapid photomultiplier and digitizer will permit flash kinetics/spectroscopic studies in the nanosecond regime and longer. Acquisition of a fluorescence microscope and accessories is also proposed so that Fluorescence Recovery After Photobleaching (FRAP) experiments may be done with either laser system. Both laser systems will be interfaced to a laboratory computer for experiment control (averaging, repetitive scanning, timing) and data manipulation. Such a facility would benefit a wide variety of NIH funded research projects in molecular and cell biology, biophysics, and biochemistry. Specific projects that will utilize this facility include: structural and mechanistic studies of copper-containing amine oxidases; transition metal-ion emission as a probe of metal and metal-nucleotide sites in proteins; fluidity domains in eukaryote plasma membranes; centriolar RNA function; photochemistry of visual pigments; determination of the mechanism of action of membrane-potential sensitive dyes; cellular adhesion, and mechanistic investigation of physiological electrotransfer reactions. Connective tissue development and diseases, cell structure, cell differentiation and development, vision, distinguishing healthy and diseased cells, and metabolism are just some of the health-related aspects of the proposed research.